Discarding broken toys

My best advice to this, is wait till he is sleeping to do these things, or not in the house. I've tried many tactics, but it never fails, they instantly become more attatched to the toys once they know they will be gone.
One thing that has worked at times, is waiting till just before a birthday or Christmas. And telling the kids, no new toys will be allowed in unless old toys go out. They can decide to pass them onto a friend, donate to charity, put in yard sale, or throw away.

I used to have to clean out their toys when they weren't around (although I'd keep the ones I knew they really loved still). It's the "Out of Sight, Out of Mind" philosophy. It worked too. There were only a couple of times where they mentioned a toy that was long gone.

Now that they are older (my youngest is now 7) they are able to understand the need to get rid of old toys to make room for new ones. We still run into some old forgotten toys being retained on sight, but for the most part they are ok with it now.

It's tricky. I usually put them in the attic for about 6 months and if they're not missed- they go. Sometimes we pick toys together to bring to Oxfam but the only problem with that is that my five year old usually sees a toy there that he wants. Some of the toys there are in fab condition so I give in. Its good recycling but it still causes clutter! I keep a big tub of plastic toys in the garage that can be used in the garden.

We have a simple solution. Whenever anything new my kids get can come in something old/broken has to go out. That lets them decide which ones to get rid of & when.

P.S. a certain amount of sneakyness might be needed beforehand to help a few things conveniently disappear to get down to the appropriate starting level.

You better look for other things to throw away. I am also in the same predicament. We have lots of toys at home and like you said some are broken and to us it is just junk but we have to see it in the eyes of a child. It is their property and they enjoy having and playing with them no matter its condition. Never throw away anything without their permission. You would have a hard time producing a toy if your kid would suddenly remember and nag you about it if you already threw it away. Put yourself in their shoes, you would not want them to throw any of your things that you have never used for a long time, would you.